edd_id.c revision 17fcfb5972977b6a3aedca6ad2aa8d1fbfbc761d
/*
* edd_id - naming of BIOS disk devices via EDD
*
* Copyright (C) 2005 John Hull <John_Hull@Dell.com>
* Copyright (C) 2005 Kay Sievers <kay.sievers@vrfy.org>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation version 2 of the License.
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE 1
#endif
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <ctype.h>
#include <string.h>
#include <errno.h>
#include <dirent.h>
#include <stdint.h>
#include "../../udev/udev.h"
static void log_fn(struct udev *udev, int priority,
const char *file, int line, const char *fn,
const char *format, va_list args)
{
vsyslog(priority, format, args);
}
int main(int argc, char *argv[])
{
struct udev *udev;
const char *node = NULL;
int i;
int export = 0;
uint32_t disk_id;
uint16_t mbr_valid;
struct dirent *dent;
int disk_fd;
int sysfs_fd;
DIR *dir = NULL;
int rc = 1;
char match[NAME_MAX] = "";
udev = udev_new();
if (udev == NULL)
goto exit;
logging_init("edd_id");
udev_set_log_fn(udev, log_fn);
for (i = 1 ; i < argc; i++) {
char *arg = argv[i];
if (strcmp(arg, "--export") == 0) {
export = 1;
} else
node = arg;
}
if (node == NULL) {
err(udev, "no node specified\n");
fprintf(stderr, "no node specified\n");
goto exit;
}
/* check for kernel support */
dir = opendir("/sys/firmware/edd");
if (dir == NULL) {
info(udev, "no kernel EDD support\n");
fprintf(stderr, "no kernel EDD support\n");
rc = 2;
goto exit;
}
disk_fd = open(node, O_RDONLY);
if (disk_fd < 0) {
info(udev, "unable to open '%s'\n", node);
fprintf(stderr, "unable to open '%s'\n", node);
rc = 3;
goto closedir;
}
/* check for valid MBR signature */
if (lseek(disk_fd, 510, SEEK_SET) < 0) {
info(udev, "seek to MBR validity failed '%s'\n", node);
rc = 4;
goto close;
}
if (read(disk_fd, &mbr_valid, sizeof(mbr_valid)) != sizeof(mbr_valid)) {
info(udev, "read MBR validity failed '%s'\n", node);
rc = 5;
goto close;
}
if (mbr_valid != 0xAA55) {
fprintf(stderr, "no valid MBR signature '%s'\n", node);
info(udev, "no valid MBR signature '%s'\n", node);
rc=6;
goto close;
}
/* read EDD signature */
if (lseek(disk_fd, 440, SEEK_SET) < 0) {
info(udev, "seek to signature failed '%s'\n", node);
rc = 7;
goto close;
}
if (read(disk_fd, &disk_id, sizeof(disk_id)) != sizeof(disk_id)) {
info(udev, "read signature failed '%s'\n", node);
rc = 8;
goto close;
}
/* all zero is invalid */
info(udev, "read id 0x%08x from '%s'\n", disk_id, node);
if (disk_id == 0) {
fprintf(stderr, "no EDD signature '%s'\n", node);
info(udev, "'%s' signature is zero\n", node);
rc = 9;
goto close;
}
/* lookup signature in sysfs to determine the name */
for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
char file[UTIL_PATH_SIZE];
char sysfs_id_buf[256];
uint32_t sysfs_id;
ssize_t size;
if (dent->d_name[0] == '.')
continue;
snprintf(file, sizeof(file), "/sys/firmware/edd/%s/mbr_signature", dent->d_name);
file[sizeof(file)-1] = '\0';
sysfs_fd = open(file, O_RDONLY);
if (sysfs_fd < 0) {
info(udev, "unable to open sysfs '%s'\n", file);
continue;
}
size = read(sysfs_fd, sysfs_id_buf, sizeof(sysfs_id_buf)-1);
close(sysfs_fd);
if (size <= 0) {
info(udev, "read sysfs '%s' failed\n", file);
continue;
}
sysfs_id_buf[size] = '\0';
info(udev, "read '%s' from '%s'\n", sysfs_id_buf, file);
sysfs_id = strtoul(sysfs_id_buf, NULL, 16);
/* look for matching value, that appears only once */
if (disk_id == sysfs_id) {
if (match[0] == '\0') {
/* store id */
util_strlcpy(match, dent->d_name, sizeof(match));
} else {
/* error, same signature for another device */
info(udev, "'%s' does not have a unique signature\n", node);
fprintf(stderr, "'%s' does not have a unique signature\n", node);
rc = 10;
goto exit;
}
}
}
if (match[0] != '\0') {
if (export)
printf("ID_EDD=%s\n", match);
else
printf("%s\n", match);
rc = 0;
}
close:
close(disk_fd);
closedir:
closedir(dir);
exit:
udev_unref(udev);
logging_close();
return rc;
}